php：来自数组的foreach的额外输出

Question

i'm trying to refresh my memory of OO & array structure. i have,

class room{
            private $people = array(
                'name' => array(
                            'height' => null,
                            'age' => null
                        )
            );

            function set($list){
                foreach($list as $person){
                    $this->people[$person['name']]['height'] = $person['height'];
                    $this->people[$person['name']]['age'] = $person['age'];
                }        
            }

            function print(){
                foreach($this->people as $k => $v){
                    echo $k . "<br>";
                    echo $v['height'] . ":" . $v['age'] . "<br><br>";
                }
            }
        }

        $input = array( array('name' => 'John', 'height' => '6.4', 'age' => '20'),
                        array('name' => 'Jane', 'height' => '5.2', 'age' => '21')
            );
        $i = new room;
        $i->set($input);
        $i->print();

the output is,

name
:

John
6.4:20

Jane
5.2:21

i'm confused as why name : appears first, when the input array only contains 2 values of each person. i am unsure if i am using my arrays correctly, could someone point out my mistake?

My overall aim of this is to have correct understanding of arrays within arrays & how to best set & get the values

Answer 1

It's because you've initialised the $people array to contain those values

private $people = array(
    'name' => array(
        'height' => null,
        'age' => null
     )
);

Change it to:

private $people = array();